94 with big problems

[huntman58]

I have a 94 xlt with some big problems that I am going to try and fix for my nephew over the next few months.
The back ground as I know it.
He was given the truck after it had sat for a few years. They replaced the intake gaskets then. This was about 3 years ago now. The truck only has about 160,000 miles on it.
The motor ran great for a few years then about 2 months ago he over heated it. now it runs realy bad with a massive miss and loss of power. looks to be blowing white smoke (steam?) out the back end . Dip stick for the oil shows way over filled and the radiator is dry also very very rusty.
PVC valve shows brown creamy film on the bottom
Lots of oil in the intake to be the sensors are covered in a wet oil coating that drips.

So our plan is top end we rebuild it. bottom end damage its junk yard city for it as I can not pull the whole motor and rebuild it because of my disability and he can not help as he is a long haul trucker gone most of the time and well he is not to mechanical and more of a hindrance then help believe me .


So how likely is it for a 4.0 OHV to creak a block? That is my main worry as short of that the bottom end should be sound and after cleaning it out with rebuilding the top end should be able to get it running again as it used to. If not I will be pulling some parts from it that I need and or may need and the rest will go away. It’s a 2x4 by the way

 

[Spartan]

I have a 94 xlt with some big problems that I am going to try and fix for my nephew over the next few months.
The back ground as I know it.
He was given the truck after it had sat for a few years. They replaced the intake gaskets then. This was about 3 years ago now. The truck only has about 160,000 miles on it.
The motor ran great for a few years then about 2 months ago he over heated it. now it runs realy bad with a massive miss and loss of power. looks to be blowing white smoke (steam?) out the back end . Dip stick for the oil shows way over filled and the radiator is dry also very very rusty.
PVC valve shows brown creamy film on the bottom
Lots of oil in the intake to be the sensors are covered in a wet oil coating that drips.

So our plan is top end we rebuild it. bottom end damage its junk yard city for it as I can not pull the whole motor and rebuild it because of my disability and he can not help as he is a long haul trucker gone most of the time and well he is not to mechanical and more of a hindrance then help believe me .


So how likely is it for a 4.0 OHV to creak a block? That is my main worry as short of that the bottom end should be sound and after cleaning it out with rebuilding the top end should be able to get it running again as it used to. If not I will be pulling some parts from it that I need and or may need and the rest will go away. It’s a 2x4 by the way

Crack a block? Not very likely..... I'd be worried that a head gasket went and you now have some issues with the rod/main bearings wearing prematurely. If the oil is way overfilled, and the PCV has brown goo on it, you likely dumped a bunch of coolant into the oil. That would also explain the white smoke..... thats usually head gasket. Its not uncommon to crack a head on one of these, so you might as well have the heads checked out by a shop before slapping gaskets on it and calling it a day. Its also possible that the manifold gaskets were not seated correctly, and are allowing oil/cololant mixing.

A word of advice: when you go to put the lower intake manifold back on, use a high tack silicone like Permatex Right stuff in the valleys, not the regular silicone that felpro puts in its mani kit. I did my intake gaskets about a year and a half ago, and literally 30 minutes after putting the sealer on there I had the truck back up and running down the interstate. That stuff seals pretty quick... Ive used it on diff covers and ran them right away without issues.

 

[Mtn_Man]

+1 on head gasket. I've seen them usually fail in the 120K-170K range as a rule. Water + oil = cutting fluid but there needs to be grit for it to be a real issue. Most likely just a top end. Get the heads checked, and it is not a bad idea to just go ahead and get them done. On my wife's 94, I went ahead and rebuilt the whole engine, but I would not recommend that unless you want to make multiple trips to the Ford dealer for the next missing o-ring or incorrect gasket that came with the kit. It's a tight tolerance motor with some tolerances being 0.0005. Ridiculous. I had the local race shop do the machining. Check the push rods and rockers for swipes and excessive wear. Very common issues there because of inadequate oiling (by design).

 

[Roadrunner777]

I suppose I would pull the heads before I made a decision on this. I am concerned about corrosion/rust on cylinder walls. If not done already, I would put a wrench on the crankshaft and see if this engine will even turn anymore.

I guess I would try and get as far into the tear-down as I could, then decide.

 

[huntman58]

+1 on head gasket. I've seen them usually fail in the 120K-170K range as a rule. Check the push rods and rockers for swipes and excessive wear. Very common issues there because of inadequate oiling (by design).

MTN_Man the intake gaskets have about 30,000 miles if that. I was told a shop did it but as we all know that really dose not mean any thing as I am sure they also shopped by price not skill. Checking the push rods and rockers I agree needs to be done from all the reading I have done on here as they are not like some of the older V motors that seamed to get plenty of oil in that area so thanks for that reminder.

I suppose I would pull the heads before I made a decision on this. I am concerned about corrosion/rust on cylinder walls. If not done already, I would put a wrench on the crankshaft and see if this engine will even turn anymore.

I guess I would try and get as far into the tear-down as I could, then decide.

Roadrunner I am lucky here as the motor is still running, badly but it will start and run just I will not run it long. plan to do the normal compression check and all before I tear any thing down as it will be about 3 to 4 weeks before he has the cash to get deep into it but will pull the heads if it shows the need ( already has so there coming off no matter what.) and then oil every thing to stop it from rusting before I get the parts.

Crack a block? Not very likely..... I'd be worried that a head gasket went and you now have some issues with the rod/main bearings wearing prematurely. If the oil is way overfilled, and the PCV has brown goo on it, you likely dumped a bunch of coolant into the oil. That would also explain the white smoke..... thats usually head gasket. Its not uncommon to crack a head on one of these, so you might as well have the heads checked out by a shop before slapping gaskets on it and calling it a day. Its also possible that the manifold gaskets were not seated correctly, and are allowing oil/cololant mixing.

A word of advice: when you go to put the lower intake manifold back on, use a high tack silicone like Permatex Right stuff .

Spartan thanks for the hint on the RYV think I will give that one a try. as for the rods and mains well he did not keep driving it when this happened so any damage would be little if at all there (hopefully) my worry was a blown gasket creaked head all things I will deal with but a creak block would make it a no go

so it seams from the majority here that a creaked block would most likely not be the case so that’s good news for him but bad for me as it means I have to work on it LOL. If the heads need work there just going to be replaced as its cheaper then having his redone around here from my pricing things out so far with mine 93.

O well he has helped me in life before many times so it’s my turn now. Thanks all for your input. I just wanted to make sure I was looking and thinking along the right track and it seams I was so thank you.

 

[scdix50]

Food for thought, oil floats on water, so your pickup screen may be under coolent when you start engine. Just a little bit of coolent will eat up your bearing surface. I would say at this point, pull it. I would set it up on end, drop the pan and check the bearings. If the bearing are not looking real nice, the only thing to do is backup and punt.

 

[Spartan]

Yeah, it doesn't need grit in it to screw up bearing quick. All that needs to happen is the oil gets diluted with coolant and looses its lubricity.... effectively making your bearings slide metal on metal. I would second the notion of using a breaker bar to see if the motor turns over before tearing it down. I personally wouldn't plan on turning that key until the work was done.

Another thing, we usually use PB blaster on the cylinders if we decide to leave the motor cracked for any amount of time past overnight. This prevents corrosion, and also might eat some of the old gasket material off. I usually put one of thise blue plastic tarps over a motor after spraying it down, just in case (i do my work outside, so i have to take more precautions.)

 

[Roadrunner777]

If I recall, they really don't want to pull the engine, I think that's a deal-breaker. I'd pull the heads, get them decked, new head gaskets, new fluids, see where it goes. I didn't realize it was running, albiet badly. There is hope!

 

[huntman58]

Well Guys I do thank you for all you Ideas and concerns. The bearings are one that I did tell him a bout as I had the same concern my self. Here is the problem tho I have no way to pull the motor and so that stops that cold. Cherry picker or not its all being done on dirt and any thing heavy sinks into the ground as it’s all sand based dirt here. Great for growing, crud for working on.

The motor has been run very little as it’s barely running so that may have saved it
To day did a compression check. Had to do it cold. starting from drivers side working back then front pass side back this is what I have.
Driver side
1= 130
2= 120
3= 135
Pass side.
4= 30
5= 60
6= 130

So I would now have to say it is definitely head or gasket on the passenger side. I also found when he did his tune up he miss routed the wires as two were burned on only the jacket and one all the way threw to the core. So as it sounded it was only running on 3 holes if that. No wonder he had no power to even get up the car trailer.
I also found only one plug that was burning good the rest all were oil fouled or starting to build up carbon deposits again all showing bad wires and blown gasket. I am sure it did not happen all of a sudden but was going out for a time and he just kept adding water never really checking his oil so I may talk to him again about the bearings but at the worse case if its just the gasket he could run some motor honey as it just has to get him by for a time tell he has the money to replace it. Again thanks as I work on it I will add to this thread so keep the ideas and helpful hints flowing as I am never above learning some thing new.

 

[huntman58]

Bringing this back up for some expert advice and for my own knowledge growth.

So far the kid dose not has the money to fix it yet but will soon. I did learn that it has only run maybe 5 minutes max with the bad head and water in the oil. This was only done to get it home one mile then onto a trailer and then off it and parked at my place. So I believe the lower end bearings should be okay.

The cylinder walls are super. No ridge and you can still see the cross hatching from the honing. Lifter and push rods all look good and I rolled the push rods on a sheet of glass and all seam right on. Looking in at the cam it also on the lobs looks great so feel good about only rebuilding the top end.

Now the bad. Intake both upper and lower all oil and carbon fowled. Exhaust manifold look clean no carbon build up. Heads well I only pulled the bad on for now. The head gasket was blown and It has 3 creaked areas and that is were I have a learning question.
Valve stems all look good same with the rocker arms and lifters. No scoring or any thing! This motor is so clean it almost looks like it was just rebuilt but I know for a fact it has not been and has 120,000 on the clock. But talk about nice and clean all I can say is wow!

Okay question. I know over heating will creak heads but is it normal to do it in multiple places or is this a sign he over heated it a few times most likely? I know he had a bad cooling system and he did cop to at lest 2 time of getting it hot. I do believe he from not taking care of the cooling system did this but now I can see why if taken care of that these motors run for so many miles. So what are your thoughts on this one super over heating time or mutable over heating meaning past boil over hot heating?

Pics are of the one head. the arrows point to the creaks and the pic of the whole head there circled in red.The cylinder with no creaks was the back one by the fire wall. This is also the Passenger side.
Thought it may help others.